Sloped screen separator that removes solids from a manure slurry

ABSTRACT

A large percentage of solids are removed from a manure slurry when the slurry is run across a sloped screen separator. The sloped screen on the separator has very small openings. In addition, the separator has a water line with spray heads formed across the sloped screen. The spray heads direct water under pressure onto the sloped screen. Further, the separator controls the air flow through the sloped screen.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a separator and, more particularly, toa sloped screen separator that removes solids from a manure slurry.

2. Description of the Related Art

When waste, such as manure, is washed away with a stream of flush water,a waste or manure slurry is formed. In agriculture, enclosed animalareas are commonly flushed with water. For example, in the dairyindustry, the alleys in a freestall barn are typically flushed twice aday with water to clean the manure from the alleys.

The treatment of manure slurry is a difficult and on-going problem inmany agricultural settings. One approach to treating manure slurry is tofill large settling pits or lagoons with the slurry. Gravity then pullsthe larger solids to the bottom. The surface water, which contains fewersolids, is typically pumped to another lagoon, where the process isrepeated. The surface water of the last lagoon is then pumped out toirrigate agricultural lands, such as alfalfa fields, or used again toflush accumulated manure from animal areas.

This approach, while relatively straightforward, has a number ofdrawbacks. One drawback is that the accumulated solids in the lagoonshave to be periodically removed at a significant expense. Anotherdrawback is that the longer the manure stays in suspension within theslurry, the more nutrients transfer from the solids to the water.

This loads the water with very high levels of nitrogen, phosphorous, andsalts. A high loading, in turn, limits the amount of irrigation that canbe performed, or requires the addition of fresh water to change theloading of the water. A further problem is that a significant amount ofgas, such as ammonia and sulfer, escapes from the slurry in a lagoon,thereby contributing to air pollution.

A common modification to this approach is to run the manure slurrythrough a separator to remove as many solids from the slurry aspossible. By removing solids from the slurry, fewer solids are depositedin the lagoons. Reducing the amount of solids that are deposited into alagoon increases the useful life of the lagoon, reduces the loading ofthe water (because solids are removed from the water), and reduces airpollution. One type of separator is a sloped screen separator.

FIG. 1 shows a cut-away perspective view that illustrates a conventionalsloped-screen separator 100, while FIG. 2 shows a side view of separator100. As shown in FIGS. 1-2, separator 100 has a back wall 110, and firstand second side walls 112 and 114 that are connected to back wall 110.Side walls 112 and 114, in turn, have openings 116 and 118.

In addition, separator 100 has a top panel 120 that is connected to thetop ends of side walls 112 and 114, and a lower panel 122 that isconnected to the bottom ends of back wall 110 and side walls 112 and114. Lower panel 122, in turn, has an opening 124.

Separator 100 also has a ledge 130 that is connected to side walls 112and 114, and a trough 132 that is connected to back wall 110, side walls112, and ledge 130. Trough 132 has a bottom side 134, and an opening 136formed in bottom side 134. Separator 100 further includes a baffle 140that is connected to side walls 112 and 114 over the longitudinal centerof trough 132.

As further shown in FIGS. 1-2, separator 100 has a front edge 142 thatis connected to side walls 112 and 114 and lower panel 122, and a slopedscreen 144 that is connected to side walls 112 arid 114, ledge 130, andfront edge 142. Sloped screen 144 typically has slotted or circularopenings 146 of 1.5 mm (approximately 0.060 of an inch).

In operation, manure slurry is pumped into trough 132 through opening136. Baffle 140 spreads the incoming slurry so that the slurry flowsevenly over the edge of ledge 130 onto sloped screen 144. The slurryflows through screen 144, with screen 144 extracting the larger solidsfrom the slurry.

Gravity pulls the larger solids extracted by screen 144 down the face ofscreen 144. The solids accumulate at the bottom of screen 144, andeventually fall off of front edge 142 where the solids are collected asstackable manure. In the dairy industry, stackable manure has a moisturecontent of roughly 75-80%.

One problem with separator 100 is that separator 100 is relativelyinefficient. Experimental results indicate that separator 100 removes,at best, approximately 16% of the solids in the slurry. Thus, eventhough separator 100 removes solids from the slurry, large amounts ofsolids continue to be added to the lagoons.

Screens with smaller openings are not utilized because the solids in theslurry plug the openings. When the openings in the screen becomeplugged, all the slurry pumped into opening 136 of trough 132 runs downthe face of screen 144 and falls off of front edge 142, causing slurryto be pumped into the work yard. The resulting clean up can be asignificant expense. Thus, due to plugging, screens with openings equalto or less than 1 mm (approximately 0.040 of an inch) are considered tobe unworkable.

With separator 100, the slurry falls through screen 144 and is collectedby lower panel 122. The slurry then flows out opening 124 where theslurry is gravity fed to a lagoon. The flow of slurry into opening 124creates a suction. If openings 116 and 118 were absent or closed, thesuction would pull air through screen 144. The flow of air throughscreen 144, however, pulls and holds solids to screen 144, therebyplugging the openings 146. Thus, openings 116 and 118 provide an airintake route that eliminates the suction across screen 144 so thatlarger solids can fall down the face of screen 144.

Screen 144 is also subject to plugging from hot summertime conditions.When the available slurry has been pumped through separator 100, solidsto varying degrees remain on the face of screen 144. In hot summertimeconditions, the solids quickly dry. When the slurry is again pumped intoseparator 100, the initial slurry runs down the face of screen 144 andfalls off front edge 142 until the moisture in the slurry unplugs theopenings 146.

One approach to preventing summertime conditions from plugging screen144 is to mist the face of screen 144 when slurry is no longer beingpumped into separator 100. This can be accomplished by placing a waterline with a number of mist heads across the front of screen 144.

When the water line is connected to a water source under pressure, suchas 2.46 kilograms per square centimeter (approximately 35 pounds persquare inch) to 3.87 kilograms per square centimeter (approximately 55pounds per square inch), the mist heads output mist in the range of 2.65liters per hour (approximately 0.7 gallons per hour) to 4.9 liters perhour (approximately 1.3 gallons per hour). The level of misting shouldnot cause solids to move down or sheet down the face of screen 144.

Thus, although sloped screen separators reduce the volume of solids thatare deposited into the holding lagoons, there is a need for a separatorthat removes more solids from the manure slurry.

SUMMARY OF THE INVENTION

The present invention provides a sloped screen separator. The slopedscreen separator of the present invention includes an input compartmentthat has an input opening and an output ledge. A manure slurry is pumpedinto the input compartment through the input opening, and flows out overthe output ledge. The separator also includes a sloped screen that isconnected to the output ledge of the input compartment. The slopedscreen has a plurality of screen openings that each have a size thatranges from a lower size to an upper size. The lower size is greaterthan a size that requires shaking before the manure slurry will fallthrough the screen openings. The upper size is equal to or less than 1mm. The manure slurry flows out over the output ledge onto the slopedscreen when the manure slurry is pumped into the input compartment.

The separator further includes a collection compartment that isconnected to the sloped screen. The collection compartment has an airflow opening and a slurry exit opening. The collection compartmentreceives a screened slurry that falls through the sloped screen when themanure slurry is pumped into the input compartment. The screened slurryflows out through the slurry exit opening.

The separator additionally includes a water pipe that is connected tothe collection compartment. The water pipe extends across the slopedscreen. Further, a plurality of spray heads are connected to the waterpipe. The spray heads output a liquid at a rate that ranges from equalto or greater than 113 liters per hour to equal to or less than 1362liters per hour per approximately 0.31 meters of the width of thescreen.

The separator also includes an air flow controller that is connected tothe collection compartment. The air flow controller controls a firstvolume of air that flows through the sloped screen as a result of thescreened slurry flowing through the slurry exit opening. The air flowcontroller variably controls a second volume of air that can flow intothe air flow opening to thereby vary the first volume of air that ispulled through the sloped screen.

The present invention also includes a method of removing solids from amanure slurry. The method includes the step of running the manure slurryover a sloped screen. The sloped screen has a plurality of screenopenings that each have a size that ranges from a lower size to an uppersize. The lower size is greater than a size that requires shaking beforethe manure slurry will fall through the screen openings. The upper sizeis equal to or less than 1 mm. The method further includes the step ofcollecting a screened slurry that falls through the sloped screen in acollection compartment.

The method additionally includes the step of spraying the manure slurrywith a liquid with sprayers at a rate that ranges from equal to orgreater than 113 liters per hour to equal to or less than 1362 litersper hour per approximately 0.31 meters of the width of the screen. Themethod also includes the step of controlling a volume of air that flowsthrough the sloped screen.

A better understanding of the features and advantages of the presentinvention will be obtained by reference to the following detaileddescription and accompanying drawings that set forth an illustrativeembodiment in which the principles of the invention are utilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-away perspective view illustrating a conventionalsloped-screen separator 100.

FIG. 2 is a side view of separator 100.

FIG. 3 is a cut-away perspective view illustrating a sloped-screenseparator 300 in accordance with the present invention.

FIG. 4 is a side view of separator 300 in accordance with the presentinvention.

FIG. 5 is a front view of separator 300 in accordance with the presentinvention.

FIG. 6 is a side view of separator 300 illustrating the operation ofseparator 300 in accordance with the present invention.

FIG. 7 is a cut-away perspective view illustrating a separator 700 inaccordance with a first alternate embodiment of the present invention.

FIG. 8 is a cut-away perspective view illustrating a separator 800 inaccordance with a second alternate embodiment of the present invention.

FIG. 9 is a cut-away perspective view illustrating a separator 900 inaccordance with a third alternate embodiment of the present invention.

FIG. 10 is a drawing illustrating a manure management system 1000 inaccordance with the present invention.

FIG. 11 is a drawing illustrating a manure management system 1100 inaccordance with the present invention.

DETAILED DESCRIPTION

FIG. 3 shows a cut-away perspective view that illustrates asloped-screen separator 300 in accordance with the present invention.FIG. 4 shows a side view of separator 300, while FIG. 5 shows a frontview of separator 300. As shown in FIGs. 3-5, separator 300 has a backwall 310, and first and second side walls 312 and 314 that are connectedto back wall 310. Side walls 312 and 314, in turn, have openings 316 and318, respectively.

In addition, separator 300 has a top panel 320 that is connected to thetop ends of side walls 312 and 314, and a lower panel 322 that isconnected to the bottom ends of back wall 310 and side walls 312 and314. Top panel 320 can be optionally omitted. Lower panel 322 has anopening 324.

Separator 300 also has a ledge 330 that is connected to side walls 312and 314, and a trough 332 that is connected to back wall 310, side walls312 and 314, and ledge 330. Trough 332 has a bottom side 334, and anopening 336 formed in bottom side 334. Separator 300 further includes abaffle 340 that is connected to side walls 312 and 314 over thelongitudinal center of trough 332.

As further shown in FIGS. 3-5, separator 300 has a front edge 342 thatis connected to side walls 312 and 314 and lower panel 322, and a slopedscreen 344 that is connected to side walls 312 and 314, ledge 330, andfront edge 342. Trough 332 defines an inflow compartment that has inputopening 336 and output ledge 330, while the region between back wall310, side walls 312 and 314, lower panel 322, front edge 342, and slopedscreen 344 define an outflow compartment. The outflow compartment has anair flow opening 316/318 and a slurry exit opening 324.

In accordance with the present invention sloped screen 344 has openings346 that range from greater than the size where slurry will not flowthrough the openings without being shaken, which is approximately 0.15mm (approximately 0.006 of an inch), to less than 1 mm (approximately0.040 of an inch). Thus, the present invention utilizes opening sizesthat were previously considered to be unworkable.

In further accordance with the present invention, separator 300 includesan air flow controller 350 connected to opening 316, and an air flowcontroller 352 connected to opening 318. Controllers 350 and 352variably control the volume of air that can flow into openings 316 and318, respectively, to thereby vary the volume of air that is pulledthrough screen 344. For example, if controllers 350 and 352 restrict thevolume of air that can flow into openings 316 and 318 to zero,effectively closing openings 316 and 318, all of the air would be pulledthrough screen 344.

In additional accordance with the present invention, separator 300 alsoincludes a water line 354 that is attached to side walls 312 and 314 andpositioned across the face of screen 344 about ¼ of the way down fromthe top of screen 344. Separator 300 further includes a number ofspaced-apart spray heads 356 that are connected to water line 354. Sprayheads 356 are positioned about 0.31 meters (approximately one foot) fromthe face of screen 344 (measured along a horizontal plane that passesthrough spray heads 356).

The section of water line 354 between side walls 312 and 314 can berotatably coupled to the remainder of water line 354 via coupler 358. Asa result, the angle at which the water output by heads 356 strikesscreen 344 can be changed by rotating the section of water line 354between side walls 312 and 314. Best results appear to be obtained whenwater strikes screen 344 at a point above spray heads 356, such asroughly an angle of 65° (measured counter clockwise from a horizontalplane passing through spray heads 356).

Spray heads 356 include two quarter-circle spray heads 360 that arepositioned next to side walls 312 and 314, and a number of half-circlespray heads 362 that are positioned between heads 360. Heads 360 can beimplemented, for example, with spray head model number S9Q sold byChampion Irrigation Products, while heads 362 can be implemented with,for example, spray heads model number S9H sold by Champion IrrigationProducts.

Different arrangements of spray heads can also be used in the presentinvention. For example, rather than using two types of spray heads, allof the spray heads can be the same. In addition, narrow width screens(where width is measured from side wall 312 to side wall 314) can beimplemented with only a single spray head.

FIG. 6 shows a side view of separator 300 that illustrates the operationof separator 300 in accordance with the present invention. As shown inFIG. 6, manure slurry 610 is pumped into trough 332 through opening 336at a rate of approximately 1703.25 liters per minute (approximately 450gallons a minute).

Baffle 340 spreads slurry 610 so that slurry 610 flows evenly over theedge of ledge 330 onto sloped screen 344 where slurry 610 is thensprayed by heads 360 and 362. Water line 354 is connected to a watersource under pressure, such as in the range of 0.70 kilograms per squarecentimeter (approximately 10 pounds per square inch) to 5.27 kilogramsper square centimeter (approximately 75 pounds per square inch).

With a pressure of approximately 3.17 kilograms per square centimeter(approximately 45 pounds per square inch), heads 360 output a spray ofabout 4.9 liters per minute (approximately 1.3 gallons per minute),while heads 362 output a spray of about 8.3 liters per minute(approximately 2.2 gallons per minute).

The amount of water sprayed on screen 344 can be adjusted by changingthe water pressure, given a spray opening with a fixed size. Less watercan be sprayed on a slurry that has a lower number of solids, while morewater can be sprayed on a slurry that has a higher number of solids. Foreach 0.31 meters (approximately one foot) of screen width (where widthis measured from side wall 312 to side wall 314), water is sprayed(approximately evenly) in the range of 1.89 to 22.71 liters per minute(approximately 0.5 to 6 gallons per minute).

In addition, controllers 350 and 352 reduce the volume of air that flowsthrough openings 316 and 318 so that a volume of air is pulled throughscreen 344. A screened slurry 612 falls through screen 344, while solids614 are extracted by screen 344. Gravity pulls solids 614 down the faceof screen 344. Solids 614 accumulate at the bottom of screen 344, andeventually fall off of front edge 342 where the solids are collected asstackable manure.

In accordance with the present invention, controllers 350 and 352 areset to pull a greater volume of air through screen 344 when the slurryhas a lower concentration of solids, and a smaller volume of air throughscreen 344 when the slurry has a higher concentration of solids.

FIG. 7 shows a cut-away perspective view of a separator 700 inaccordance with a first alternate embodiment of the present invention.Separator 700 is similar to separator 300 and, as a result, utilizes thesame reference numerals to designate the structures which are common toboth separators.

As shown in FIG. 7, separator 700 differs from separator 300 in thatseparator 700 has a plurality of openings 710 on each side wall 312 and314 rather than single openings 316 and 318. Each opening 710, in turn,has a rotatably-connected cover 712. In operation, the volume of airpulled through screen 344 is determined by the number of openings 710that are open, partially opened, or closed. For example, if all of theopenings 710 were closed by covers 712, all of the air would be pulledthrough screen 344.

FIG. 8 shows a cut-away perspective view of a separator 800 inaccordance with a second alternate embodiment of the present invention.Separator 800 is similar to separator 300 and, as a result, utilizes thesame reference numerals to designate the structures which are common toboth separators.

As shown in FIG. 8, separator 800 differs from separator 300 in thatseparator 800 does not have air flow controllers 350 and 352. Inseparator 800, openings 316 and 318 are formed to be large enough toprevent solids from being pulled into screen 844 as a result of slurryflowing out of opening 324. Separator 800 further differs from separator300 in that separator 800 has openings 846 ranging from about 0.51 mm(approximately 0.020 of an inch), to about 1.78 mm (approximately 0.070of an inch). Experimental results taken with a screen having 0.89 mm(approximately 0.035 of an inch) openings indicate that, although not asdramatic as separator 300, separator 800 also removes more solids thandoes conventional separator 100.

FIG. 9 shows a cut-away perspective view of a separator 900 inaccordance with a third alternate embodiment of the present invention.Separator 900 is similar to separator 300 and, as a result, utilizes thesame reference numerals to designate the structures which are common toboth separators.

As shown in FIG. 9, separator 900 differs from separator 300 in thatseparator 900 does not have air flow controllers 350 and 352, water line354, or spray heads 356. Separator 900 further differs from separator300 in that separator 900 has openings 946 in screen 944 ranging fromabout 0.51 mm (approximately 0.020 of an inch), to less than 1 mm(approximately 0.040 of an inch). Experimental results taken fromseparator 900 using about 0.89 mm (approximately 0.035 of an inch)openings indicate that as the percentage of solids in the slurry drops,the size of the openings can be reduced.

FIG. 10 shows a drawing that illustrates a manure management system 1000in accordance with the present invention. As shown in FIG. 10, system1000 includes an initial holding basin 1010, a first sloped-screenseparator 1012, and a pumping system 1014 that pumps slurry from basin1010 to separator 1012. Separator 1012, which has screen openings of afirst size, can be implemented with separators 300, 700, 800, or 900.Separator 100 can alternately be used to implement separator 1012.

System 1000 further includes a second sloped-screen separator 1022 thatreceives slurry from separator 1012, a lagoon 1030 that receives slurryfrom separator 1022, and a pumping system 1032 that is connected tolagoon 1030. Separator 1022, which has screen openings of a second size,can be implemented with separators 300 and 700.

In accordance with the present invention, separator 1012 has screenopenings that are larger than the screen openings of separator 1022. Forexample, separator 1012 can have openings of about 0.89 mm(approximately 0.035 of an inch) while separator 1022 can have openingsof about 0.25 mm (approximately 0.010 of an inch). As another example,separator 1012 can have openings of about 1.52 mm (approximately 0.060of an inch) while separator 1022 can have openings of about 0.25 mm(approximately 0.010 of an inch).

In operation, a flushed manure slurry 1040 is collected in holding basin1010. Holding basin 1010 need only be large enough to hold the slurryfrom a single flushing, although additional capacity would be needed ifback up pumping capacity is unavailable. As a result, holding basin 1010can be small in size.

Pumping system 1014 then pumps slurry 1040 from basin 1010 intoseparator 1012. Separator 1012 outputs a once-screened slurry 1042 thatis gravity fed into separator 1022, and an amount of stackable solidsthat fall over front edge 342 of separator 1012. Separator 1022 outputsa twice-screened slurry 1044 that is gravity fed into lagoon 1030, andan amount of stackable solids that fall over front edge 342 of separator1022. Pumping system 1032 then pumps twice-screened slurry 1044 out forirrigation, such as for alfalfa fields, or flushing.

FIG. 11 shows a drawing that illustrates a manure management system 1100in accordance with the present invention. System 1100 is similar tosystem 1000 and, as a result, utilizes the same reference numerals todesignate the structures which are common to both systems.

As shown in FIG. 11, system 1100 differs from system 1000 in that system1000 includes a second holding basin 1110 that receives slurry fromseparator 1012, and a pumping system 1112 that pumps slurry from basin1110 to separator 1022. System 1100 operates the same as system 1000except that once-screened slurry 1042 output by separator 1012 isgravity fed into basin 1110, and pumping system 1112 then pumpsonce-screened slurry 1042 into separator 1022. Basin 1110 can be madequite small if slurry is pumped into separator 1022 before pumpingsystem 1014 stops pumping slurry from basin 1010.

When reused for flushing, experimental results have indicated that theuse of twice-screened slurry 1044 has a scrubbing effect that tends toclean the flushed areas. In addition, recycling and reusingtwice-screened slurry 1044 significantly minimizes the amount of freshwater that needs to be introduced into the flushing system.

Experimental results taken from twice-screened slurry 1044 indicate thatthe use of separators 1012 and 1022 removes 90% and more of the solidsfrom slurry 1040. This is in stark contrast to the 16% of the solidsthat are removed by prior-art separator 100. One benefit of thisdramatic increase in the percentage of removed solids is that the usefullife of the lagoons is significantly extended.

Another benefit is that if slurry 1040 is processed within a few hoursafter being collected, the amount of nutrients and salts that are loadedinto twice-screened slurry 1044 is significantly reduced. Experimentalresults indicate that twice-screened slurry 1044 has nitrogen levelsthat are about twice the levels of normal cow manure, a dramaticreduction in the amount of nitrogen that is present in unscreened slurrytaken from a settling lagoon.

It should be understood that various alternatives to the method of theinvention described herein may be employed in practicing the invention.For example, although openings 316 and 318 (and 710) are show as formedin side walls 312 and 314, respectively, openings 316 and 318 (and 710)can be formed in any vertical surface that forms a part of the outflowcompartment, such as back wall 310.

Further, rather than using openings 316 and 318, a single opening canalternately be used. Thus, it is intended that the following claimsdefine the scope of the invention and that methods and structures withinthe scope of these claims and their equivalents be covered thereby.

What is claimed is:
 1. A method for removing solids from a manureslurry, the method comprising the steps of: running the manure slurryover a sloped screen, the sloped screen having a plurality of screenopenings and a width, the screen openings having a size that ranges froma lower size to an upper size, the lower size being greater than a sizethat requires shaking before the manure slurry will fall through thescreen openings, the upper size being equal to or less than 1 mm; andcollecting a screened slurry that falls through the sloped screen in acollection compartment.
 2. The method of claims 1 and further comprisingthe step of spraying the manure slurry with a liquid with sprayers at arate, the rate ranging from equal to or greater than 113 liters per hourto equal to or less than 1362 liters per hour per approximately 0.31meters of the width.
 3. The method of claim 2 and further comprising thestep of controlling a volume of air that flows through the slopedscreen.
 4. A method for removing solids from a manure slurry, the methodcomprising the steps of: running the manure slurry over a sloped screen,the sloped screen having a plurality of screen openings and a width, thescreen openings having a size that ranges from about 0.18 mm to equal toor less than 1 mm; and collecting a screened slurry that falls throughthe sloped screen in a collection compartment.
 5. The method of claim 4and further comprising the step of spraying the manure slurry with aliquid with sprayers at a rate, the rate ranging from equal to orgreater than 113 liters per hour to equal to or less than 1362 litersper hour per approximately 0.31 meters of the width.
 6. The method ofclaim 5 and further comprising the step of controlling a volume of airthat flows through the sloped screen.
 7. A method for removing solidsfrom a manure slurry, the method comprising the steps of: running themanure slurry over a sloped screen, the sloped screen having a pluralityof screen openings and a width, the screen openings having a size thatranges from 0.23 mm to equal to or less than 0.89 mm; and collecting ascreened slurry that falls through the sloped screen in a collectioncompartment.
 8. The method of claim 7 and further comprising the step ofspraying the manure slurry with a liquid with sprayers at a rate, therate ranging from equal to or greater than 113 liters per hour to equalto or less than 1362 liters per hour per approximately 0.31 meters ofthe width.
 9. A method for removing solids from a manure slurry, themethod comprising the steps of: running the manure slurry over a slopedscreen, the sloped screen having a width and a plurality of screenopenings; spraying the manure slurry with a liquid with sprayers at arate, the rate ranging from equal to or greater than 113 liters per hourto equal to or less than 1362 liters per hour per approximately 0.31meters of the width; and collecting a screened slurry that falls throughthe sloped screen in a collection compartment.
 10. The method of claim 9and further comprising the step of controlling a volume of air thatflows through the sloped screen.
 11. A method for removing solids from amanure slurry, the method comprising the steps of: running the manureslurry over a sloped screen, the sloped screen having a width and aplurality of screen openings; controlling a volume of air that flowsthrough the sloped screen; collecting a screened slurry that fallsthrough the sloped screen in a collection compartment; and spraying themanure slurry with a liquid with sprayers at a rate, the rate rangingfrom equal to or greater than 113 liters per hour to equal to or lessthan 1362 liters per hour per approximately 0.31 meters of the width.12. A method for removing solids from a manure slurry, the methodcomprising the steps of: running the manure slurry over a sloped screen,the sloped screen having a width and a plurality of screen openings;spraying the manure slurry with a liquid with a sprayer at a rate, therate ranging from equal to or greater than 113 liters per hour to equalto or less than 1362 liters per hour per approximately 0.31 meters ofthe width; and collecting a screened slurry that falls through thesloped screen in a collection compartment.